linux-cve-announce - CVE-2025-22045: x86/mm: Fix flush_tlb_range() when used for zapping normal PMDs

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Message-ID: <2025041601-CVE-2025-22045-049d@gregkh>
Date: Wed, 16 Apr 2025 16:12:16 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2025-22045: x86/mm: Fix flush_tlb_range() when used for zapping normal PMDs

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

x86/mm: Fix flush_tlb_range() when used for zapping normal PMDs

On the following path, flush_tlb_range() can be used for zapping normal
PMD entries (PMD entries that point to page tables) together with the PTE
entries in the pointed-to page table:

    collapse_pte_mapped_thp
      pmdp_collapse_flush
        flush_tlb_range

The arm64 version of flush_tlb_range() has a comment describing that it can
be used for page table removal, and does not use any last-level
invalidation optimizations. Fix the X86 version by making it behave the
same way.

Currently, X86 only uses this information for the following two purposes,
which I think means the issue doesn't have much impact:

 - In native_flush_tlb_multi() for checking if lazy TLB CPUs need to be
   IPI'd to avoid issues with speculative page table walks.
 - In Hyper-V TLB paravirtualization, again for lazy TLB stuff.

The patch "x86/mm: only invalidate final translations with INVLPGB" which
is currently under review (see
<https://lore.kernel.org/all/20241230175550.4046587-13-riel@surriel.com/>)
would probably be making the impact of this a lot worse.

The Linux kernel CVE team has assigned CVE-2025-22045 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 4.20 with commit 016c4d92cd16f569c6485ae62b076c1a4b779536 and fixed in 5.4.292 with commit 618d5612ecb7bfc1c85342daafeb2b47e29e77a3
	Issue introduced in 4.20 with commit 016c4d92cd16f569c6485ae62b076c1a4b779536 and fixed in 5.10.236 with commit 556d446068f90981e5d71ca686bdaccdd545d491
	Issue introduced in 4.20 with commit 016c4d92cd16f569c6485ae62b076c1a4b779536 and fixed in 5.15.180 with commit 0a8f806ea6b5dd64b3d1f05ff774817d5f7ddbd1
	Issue introduced in 4.20 with commit 016c4d92cd16f569c6485ae62b076c1a4b779536 and fixed in 6.1.134 with commit 0708fd6bd8161871bfbadced2ca4319b84ab44fe
	Issue introduced in 4.20 with commit 016c4d92cd16f569c6485ae62b076c1a4b779536 and fixed in 6.6.87 with commit 7085895c59e4057ffae17f58990ccb630087d0d2
	Issue introduced in 4.20 with commit 016c4d92cd16f569c6485ae62b076c1a4b779536 and fixed in 6.12.23 with commit 93224deb50a8d20df3884f3672ce9f982129aa50
	Issue introduced in 4.20 with commit 016c4d92cd16f569c6485ae62b076c1a4b779536 and fixed in 6.13.11 with commit 320ac1af4c0bdb92c864dc9250d1329234820edf
	Issue introduced in 4.20 with commit 016c4d92cd16f569c6485ae62b076c1a4b779536 and fixed in 6.14.2 with commit 78d6f9a9eb2a5da6fcbd76d6191d24b0dcc321be
	Issue introduced in 4.20 with commit 016c4d92cd16f569c6485ae62b076c1a4b779536 and fixed in 6.15-rc1 with commit 3ef938c3503563bfc2ac15083557f880d29c2e64

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-22045
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	arch/x86/include/asm/tlbflush.h


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/618d5612ecb7bfc1c85342daafeb2b47e29e77a3
	https://git.kernel.org/stable/c/556d446068f90981e5d71ca686bdaccdd545d491
	https://git.kernel.org/stable/c/0a8f806ea6b5dd64b3d1f05ff774817d5f7ddbd1
	https://git.kernel.org/stable/c/0708fd6bd8161871bfbadced2ca4319b84ab44fe
	https://git.kernel.org/stable/c/7085895c59e4057ffae17f58990ccb630087d0d2
	https://git.kernel.org/stable/c/93224deb50a8d20df3884f3672ce9f982129aa50
	https://git.kernel.org/stable/c/320ac1af4c0bdb92c864dc9250d1329234820edf
	https://git.kernel.org/stable/c/78d6f9a9eb2a5da6fcbd76d6191d24b0dcc321be
	https://git.kernel.org/stable/c/3ef938c3503563bfc2ac15083557f880d29c2e64